The present disclosure relates to laser diodes characterized by multi-wavelength emission and, more particularly, to distributed Bragg reflector (DBR) laser diodes where the wavelength selective grating of the laser diode generates multiple wavelength reflections simultaneously in the laser output spectrum. The present disclosure also relates to the use of a multi-wavelength laser diodes as a pump source for frequency up-conversion through second-harmonic (SHG) or sum-frequency (SFG) generation, as can be applied for conversion of an IR pump to emission in the green portion of the optical spectrum, for example.